This invention relates to inhibiting distillate fuel oil fouling, which is manifested by color degradation, particulate formation and gum generation in distillate fuel oils.
During hydrocarbon processing, transportation and storage, the hydrocarbons deteriorate, particularly when subjected to elevated temperatures. The deterioration usually results in the formation of sediment, sludge, or gum and can manifest itself visibly by color deterioration. Color deterioration may prevent the sale of fuel oil. Sediment, sludge, or gum formation may cause clogging of equipment or fouling of engines and processing equipment, such as, for example, heat exchangers, compressors, furnaces, reactors and distillation equipment. The fouling is caused by the gradual accumulation of high molecular weight polymeric material on the inside surfaces of the equipment. As fouling continues, the efficiency of the operation associated with hydrocarbon processing equipment, such as heat exchangers, compressors, furnaces, reactors and distillation equipment, decreases. The hydrocarbons which may result in significant fouling include the straight run distillates (kerosene, diesel, jet), naphthas, catalytic cracker feedstocks (gas oils), light and heavy cycle oils, coker naphthas, residual fuel oils, petrochemical plant feedstocks, and hydrotreated products of the above.
It has been found that in some types of color degradation, particulate formation and gum generation can be traced to the presence of heteroaromatic compounds in the hydrocarbons. It is believed that these compounds react and/or oxidize to cause degradation of the hydrocarbons. Therefore, it is desirable to develop methods for preventing the reactions and/or oxidation of these compounds and thus the degradation of the hydrocarbons.